PHP connection MySQL exception under Linux

PHP connection MySQL error on Linux
My PHP version is the 5.2.13,ysql version is 5.0, when executing the following statement
$con = mysql_connect ($host _port, $user, $passwd);
Reported an error:
PHP Fatal error:call to undefined function mysql_connect ()

I looked at the information in the next phpinfo () with the following two options: '--with-mysql=shared,/usr '--with-mysqli=shared,/usr/bin/mysql_config '
In addition, in my/etc/php.ini view Extension_dir = "/usr/lib64/php/modules", in the/usr/lib64/php/modules this directory, but found no mysql.so files.
I tried it under:
Put
/usr/lib64/perl5/vendor_perl/5.8.8/x86_64-linux-thread-multi/auto/dbd/mysql/mysql.so
Under the mysql.so copy to/usr/lib64/php/modules, then execute once
$con = mysql_connect ($host _port, $user, $passwd);
Still reported: Call to undefined function mysql_connect ()

Excuse me, do I have to pack some bags? Like Php-mysql and papache2-mod_php, these two bags.
------Solution--------------------
Has MySQL started yet? Service MySQL start or service mysqld start
Or look at it and error log

------Solution--------------------
You look at the permissions of the user who executed PHP on mysql.so.

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